The present invention relates to a system for improved fuel efficiency in combustion engines utilizing a turbocharger by limiting the boost by the turbocharger control system under specified speed conditions.
The present art concerning turbocharger systems in combustion engines monitor engine power requirements by various measurements such as exhaust temperature, charging pressure, etc. When specific requirements call for more horsepower a booster is activated which will increase the air and fuel. This increase creates more horsepower until a set speed is obtained. When a set speed (for example, cruise control) is obtained, the booster will decrease or deactivate.
U.S. Pat. No. 4,418,536 1981 to Deutschmann describes exhaust gas turbochargers, with one or more of the exhaust gas turbochargers being adapted to be disconnected during partial load.
U.S. Pat. No. 4,461,149 1981 to Suzuki describes a supercharger control system for an internal combustion engine by applying a supercharge pressure to the engine by driving a compressor with a turbine rotated by the energy of the exhaust gas.
U.S. Pat. No. 4,463,565 1982 to Rydquist et al. describes a system for preventing knocking combustion in a turbocharged Otto engine via a knock detector and microprocessor.
U.S. Pat. No. 4,467,607 1982 to Rydquist et al. describes a system for controlling the inlet pressure in a combustion engine including a microprocessor.
U.S. Pat. No. 4,499,885 1983 to Weissenbach describes a supplemental fuel system for a combustion engine having a primary fuel supply and a supplemental fuel supply.
U.S. Pat. No. 4,505,117 1982 to Matsuoka describes an internal combustion engine including a turbocharger and a controller for the turbocharger.
U.S. Pat. No. 4,528,816 1982 to Arnaud describes an apparatus for pneumatic control of supercharging pressure in a turbocompressed engine.
U.S. Pat. No. 4,679,398 1985 to Nishiguchi et al. describes an apparatus for controlling a variable geometry turbocharger including a compressor and a turbine coupled to the compressor and comprises a variable capacity device for varying the flow rate of an exhaust gas introduced into the turbocharger in the low speed state of an engine and an exhaust gas bypass device bypassing the variable capacity device and the turbine to control the flow rate of the exhaust in the high speed state of the engine.
U.S. Pat. No. 5,228,292 to Hanauer et al. describes an arrangement for adjusting the boost pressure in an internal-combustion engine, supercharged by an exhaust-gas turbocharger with adjustable turbine diffuser, to a predetermined desired boost-pressure value dependent on the operating point.
U.S. Pat. No. 5,174,119 1991 to Hanauer et al. describes a process for adjusting the boost pressure in an internal-combustion engine, supercharged by an exhaust-gas turbocharger with adjustable turbine diffuser, to a predetermined desired boost-pressure value dependent on the operating point.
U.S. Pat. No. 5,850,737 1996 to Aschner et al. describes a process for adjustment of the charging pressure in an internal-combustion engine exhaust gas turbocharger having an adjustable turbine geometry, to a pre-determined operating-point-dependent desired charging pressure level.
U.S. Pat. No. 6,155,049 1999 to Bischoff describes a method of controlling the charge air mass flow of an internal combustion engine having an exhaust gas turbocharger with adjustable turbine geometry and a control unit for controlling the operation of the turbocharger.
U.S. Pat. No. 6,250,260 Bl 1998 to Green describes a system and assembly for modifying a diesel powered electric generator.
What is needed is a process for allowing the vehicle to have a decrease in fuel consumption for a small sacrifice in vehicle speed. What is also needed is a process to allow the vehicle private owner (or company owner) to set maximum limits of boost speed under specific conditions.
The main aspect of the present invention is to provide a means for fuel optimization within specific limits of speed and boost pressure to a combustion engine.
Another aspect of the present invention is to limit a vehicle boost pressure within specified limits when the speed of a vehicle is at or drops below cruise set speed.
Another aspect of the present invention is to allow for a vehicle owner (private or company) to have the ability to vary the boost pressure set limit when the speed of a vehicle is at or drops below cruise set speed.
Another aspect of the present invention is to provide for an automatic means of fuel economization, the preferred embodiment.
Another aspect of the present invention is to provide for a semi-automatic means of fuel economization, an alternate embodiment.
Another aspect of the present invention is to provide for a manual means of fuel economization, an alternate embodiment.
Other aspects of this invention will appear from the following description and appended claims, reference being made to the accompanying drawings forming a part of this specification wherein like reference characters designate corresponding parts in the several views.
Combustion engines with turbochargers will operate at optimal engine performance with an Electronic Control Module (ECM) or other means for controlling the turbocharger. The ECM, operating in normal control mode, will monitor standard engine inputs such as exhaust gas temperature, etc. The control systems of prior art will provide the engine with a quick increase in horsepower (HP) when required. For example, when cresting a hill and the speed decreases below the set cruise speed, a vehicle""s turbocharger will increase boost until the set cruse speed is re-obtained. Thus, if a hill crest, headwind, or a slight incline results in a vehicle going below cruise set speed, the turbo will go into maximum boost until the vehicle regains its set cruise speed. Although this method maintains a set cruise speed at minimal loss of time, it does not offer any alternative of fuel savings for some additional minimal loss of time.
All xe2x80x9cFuel Economizer Systemxe2x80x9d (FES) equipped vehicles shall have a xe2x80x9cdrop-outxe2x80x9d speed, which is determined by the engine manufacturer. The drop-out speed is that speed below a set cruise control speed at which the cruise control xe2x80x9cdisconnectsxe2x80x9d. Drop-out speeds are to be non-adjustable and will vary with different transmission and differential combinations as set by the engine and vehicle manufacturer.
The present invention FES would consist of circuitry to active the system, to accept input of a boost pressure limit (BPL), to accept input of a minimal speed (economy set-speed or ESS), sensors to insure that the cruise control is xe2x80x9cONxe2x80x9d, vehicle real-time speed sensors, vehicle drop-out speed inputs, etc. The FES circuitry might also have a display showing status of the system (ON or OFF), ESS and BPL settings. The present invention Fuel Economizer System (FES) will function to limit the engine""s turbocharger boost and fuel consumption when the vehicle is running at highway speeds. The FES can be used for Owner/Operator specified vehicles and also for fleet specified vehicles.
The FES will allow for normal Electronic Engine Control (EEC) when the vehicle speed is below the drop-out speed or when the vehicle speed is below a pre-determined xe2x80x9ceconomy-set-speedxe2x80x9d (ESS). The ESS will be a speed higher than the drop-out speed but below set cruise speed.
In the preferred embodiment of the present invention, the FES will operate under the following required conditions:
a) The FES is set to the xe2x80x9conxe2x80x9d position,
b) The vehicle cruise control is xe2x80x9conxe2x80x9d,
c) The vehicle speed is above the drop-out speed, and
d) An ESS speed is preset and the vehicle speed is above the ESS.
e) A preset (or variable) maximum boost limitation is present.
Given that the above conditions are satisfied, the present invention FES will act as follows:
a) Provide an input to the ECM to limit the turbo boost to a specific preset value, such value set by the operator/owner (as a variable) or by the fleet owner (as a constant). The ECM will constantly monitor and limit the turbo boost to the value set by the FES. Under such conditions the ECM will regulate the fuel flow to each cylinder based on a fuel rate predetermined by the engine manufacture. Such fuel rate will be the fuel consumption that allows for the cleanest emissions and optimum horsepower at a given engine rpm and turbo pressure.
b) Monitor the required conditions and input the ECM to operate in a normal or limited boost mode.
If the above-required conditions are not met the FES will provide an input to the ECM to control the engine in a normal mode under normal operating conditions concerning boost and fuel conditions.
If the required conditions are satisfied, the FES will allow for speed recovery at a controlled boost in order to optimize the fuel efficiency. For example, if there is an incline in the road. If the distance traveled during maximum boost is 300 yards (under normal operating conditions) in order to regain set cruise speed, for example, the vehicle may only get 2.5 miles per gallon (MPG) during that distance in which the engine is at maximum boost (35 pounds per square inch xe2x80x9cpsixe2x80x9d, for example). The present invention will allow for a limitation of the turbo boost (10 psi for example). It may take 400 yards to regain the engine set cruise speed, but the fuel consumption can be improved to 6.8 to 7.0 MPG for that 400 yards.
Owner/operator vehicles can be set up to operate with three toggle switches on the vehicle""s dash. The switches would function as follows:
1. A FES toggle switch with an xe2x80x9cONxe2x80x9d and xe2x80x9cOFFxe2x80x9d position. In the xe2x80x9cOFFxe2x80x9d position the vehicle will bypass all FES controls. The switch can have a pilot light to indicate the xe2x80x9cONxe2x80x9d position.
2. A second momentary contact type toggle switch to xe2x80x9cRaisexe2x80x9d or xe2x80x9cLowerxe2x80x9d boost limit pressure upon contact in an up or down position respectively.
3. A third momentary contact toggle switch to xe2x80x9cRaisexe2x80x9d or xe2x80x9cLowerxe2x80x9d the Economy Set Speed upon contact in an up or down position respectively.
A simple display could show the status of the above settings.
Although the above is described with toggle switches, other control means can be designed, such as touch displays, variable control knobs, etc.
Fleet specified FES control could be accomplished by values (turbo boost limit, dropout and ESS) pre-set into the electronic memory of the ECM by the fleet""s mechanics. In this way, the fleet ownership can control the FES settings as desired. A fleet owner can alternatively elect to also use controls as described above for owner/operator controls.
An example of the FES operation is presented as follows:
1. The vehicle cruise control is set at 70 MPH.
2. The FES is set to maintain a boost pressure of 10 psi max.
3. The ESS is set to 62 MPH.
With the settings above, if the vehicles, speed is 63 MPH or more, the FES will limit turbo boost to 10 psi max. When the speed of the vehicle drops to 62 MPH or less, the ECM automatically bypasses the FES and returns to its xe2x80x9cnormalxe2x80x9d turbo boost and fuel consumption control.
When operating with the FES in the xe2x80x9cONxe2x80x9d position a vehicle will have a limit on the turbo boost allowed as long as its speed is above the ESS. During these conditions of limited boost, the MPG will increase and have a positive effect on the average MPG over a long distance. By use of the FES the vehicle will see an increase in average MPG and thus have a positive gain in fuel efficiency. The owner of the present invention has shown xe2x80x9cat leastxe2x80x9d a one-mile per gallon gain when operating a vehicle over a year""s timeframe.
The following is an example of savings that are potentially available at an increase of 1-MPG assuming accuracy of the following estimated figures:
1. That there are approximately 6 million diesel powered over-the-road trucks.
2. That the average fuel consumption is approximately 6 MPG.
3. That average miles driven per vehicle are approximately 100,000 miles.
4. That average fuel consumption is approximately 16,667 gallons per vehicle.
5. A savings of 1 MPG would result in an average MPG of 7. Thus, the result would be to reduce fuel consumption from 16,667 gallons to 14,286 gallons, a savings of 2381 gallons per vehicle. The net savings for 6 million trucks would amount to 14,286,000,000 gallons of fuel. That is over 14 billion gallons of fuel. That equates to hundreds of millions of barrels of crude oil that is saved per year.
An alternate embodiment of the present invention is a to provide for a semi-automatic mode of operation. In this mode a boost pressure regulator would be installed in the turbocharger system to be activated with an ON/OFF switch. The boost regulator would act as a xe2x80x9climiterxe2x80x9d, that is, it would limit the boost to a predetermined level (10 psi for example). In the xe2x80x9cOFFxe2x80x9d position the normal turbocharger operation would prevail. In the xe2x80x9cONxe2x80x9d position, the boost pressure regulator would bypass the normal turbocharger boost system. When the vehicle speed goes above the ESS (as determined by the operator), the operator would switch the boost regulator switch to an xe2x80x9cONxe2x80x9d position. Boost regulation would remain in effect until the speed of the vehicle would drop below the ESS. At that time an alarm (audio or video) would activate and the operator would turn the boost regulator to the xe2x80x9cOFFxe2x80x9d position. In this manner, the vehicle would operate in a semi-automatic mode regulating (limiting) the boost pressure automatically with vehicle speed greater than the ESS. The semi-automatic mode of operation will function as described above independent of the cruise control setting.
Example:
Trucker xe2x80x9cBobxe2x80x9d drives his rig (vehicle), weighing 80,000 pounds of gross vehicle weight (GVW), at 65 mph on a level stretch of interstate highway. His vehicle has a boost pressure regulator (boost pressure limiter) and a turbo boost gauge installed. It should be noted that a boost pressure gauge can be labeled with various identifiers such as xe2x80x9cturbo boost gauge, turbo, pressure gauge, boost pressure gauge, etc.xe2x80x9d The boost pressure regulator is set to limit the boost pressure to 10 psi maximum, for example. Further, xe2x80x9cBobxe2x80x9d decides not to drive slower than 60 mph nor faster than 75 mph, all in the highest gear and with the cruise control xe2x80x9coffxe2x80x9d. xe2x80x9cBobxe2x80x9d has thus determined his ESS to be 60 mph. He then monitors the speed gauge and, if the speed is above 60 mph (ESS), he sets the boost regulator switch to xe2x80x9cONxe2x80x9d. The turbo boost pressure would then be limited to 10 psi, that is, the boost pressure would vary between 0 and 10 psi max) during vehicle operation and thus increase fuel economy. If the vehicle drops below the ESS, an alarm would sound and xe2x80x9cBobxe2x80x9d would set the boost regulator switch to xe2x80x9cOFFxe2x80x9d. If no alarm were installed, xe2x80x9cBobxe2x80x9d would have to manually monitor the speed. Once the vehicle speed is below the ESS and the boost regulator switch is xe2x80x9cOFFxe2x80x9d, xe2x80x9cBobxe2x80x9d would operate the vehicle in a normal mode. That is, he would either apply more pressure to the accelerator pedal (increasing the boost) or shift to a lower gear or both. It should be noted that the gear may or may not be the xe2x80x9chighestxe2x80x9d gear. A vehicle may operate in a high gear that is not necessarily the xe2x80x9chighest gearxe2x80x9d depending on such factors as the speed limit, the grade, etc. Note: If Bob had elected to keep the cruise control off, the upper speed limit would be determined by Bob""s application of pressure on the accelerator pedal. Another alternate embodiment of the present invention would be a manual mode. A manual mode would not be nearly as efficient as the operator would have to monitor several variables. In this mode, it would be very desirable for the vehicle to have a fuel system monitor and real time MPG monitor installed for the operator""s convenience. The vehicle would require a cruise control and a turbo boost gauge. With the cruise control xe2x80x9cONxe2x80x9d, the operator would monitor vehicle speed and the turbo boost gauge. Monitoring the vehicle speed, if the speed is above the operators predetermined ESS, the operator would monitor boost pressure and try to limit boost pressure to a predetermined level (10 psi for example). Boost pressure would be limited by physically applying less pressure to the accelerator pedal. The real time MPG monitor would show an increase in instantaneous MPG as the boost is decreased and held to a predetermined value.
Example Of Manual Control:
Trucker xe2x80x9cBobxe2x80x9d drives his rig (vehicle), weighing 80,000 pounds of gross vehicle weight (GVW), at 65 mph on a level stretch of interstate highway and determines that his boost pressure limit (BPL) can be 10 psi maximum. Downgrades in the road can increase his speed. Further he decides not to drive slower than 60 mph nor faster than 75 mph, all in the highest gear and with the cruise control xe2x80x9coffxe2x80x9d. xe2x80x9cBobxe2x80x9d has thus determined his ESS to be 60 mph and his BPL to be 10 psi. He then monitors the speed gauge and, if the speed is above 60 mph (ESS) and below 75 mph, he limits the boost pressure to 10 psi, or lower, by controlling his foot pressure on the accelerator pedal.